1. Field of the Invention
The invention relates in general to digital video recording, and more particularly to a method and apparatus for generating thumbnails for digital video recording.
2. Description of the Related Art
In form of rougher or smaller icons or images, thumbnails are a presentation of larger images or picture frames according to related techniques for allowing users to more quickly identify a desired target. The architecture of a conventional video recorder frequently results in certain issues, especially user inconveniences. For example, when a conventional digital video recorder performs a simple operation of fast-forwarding or rewinding along a time axis, a user can only identify a target image during the fast-forward or rewind process through guessing a time point of the target image. That is to say, such method, in which users can only search for the target image by merely recalling a corresponding time point or by constantly fast-forwarding or rewinding, is quite inefficient. As another example, the conventional digital video recorder may also display a certain intra-frame (I frame) for users to guess, estimate or compare a time point at which a target image appears. However, an original transport stream does not carry complete image messages of other types of frames such as predictive frames (P frames) and bi-directional frames (B frames), and so no image information can be directly converted from the image messages. Hence, users can only observe an image of an I frame near the expected time point rather than the precise target image, meaning that such method yields an imprecise result. Further, this architecture needs to support high-level hardware devices such as a graphics engine that occupies the performance of a processor. Therefore, there is a need for a solution for enhancing the performance of digital video recorders as well as user viewing experiences.